you have put all the blacks together.
one of the black wires go to the switch.
u need to find the cable which goes to the switch from the light.
there will be one red one black and an earth.
at the light the black that comes from the switch goes on its own with the brown wire from the new light.
all the red wires go together in a connector block.(normally 3)
there should be two black wires spare. they go with the blue wire from the new light.
all the earths connect together.
this should work